Killing a Man: Confessions of an Interrogator - New York Times

[QUOTE] ... Then something happened to me. I started to lose it.  I was in an altered state, where my mental processes broke down.  It was as if the scene had been rehearsed and choreographed. My role was to punch him, and his role was to repeat his line.  This went on for about two minutes, and then he stopped repeating.

Lastours felt his pulse and said, "He's dead. And he didn't talk."…

I was horrified by what I had done. I had killed a defenseless man. I had not intended to kill him, but that didn't make him any less dead. [END QUOTE]

Killing a Man: Confessions of an Interrogator - New York Times.